Pancreatic Lipase Hydrolysis of Cow Milk Fat

Knowledge of the position of individual fatty acids within the trig'lycerides is necessary to the understanding of the utilization of a fat. Pancreatic lipase hydrolysis to convert triglycerides to 2-monoglycerides has been used to study this type of glyceride structure in roany food fats, but it has recently been claimed that it cannot be used with cow milk fat because butyric acid is hydrolyzed more rapidly than the other acids. This study was undertaken to determine if there were conditions under which this technique could be applied validly to milk fat. The criteria set forth for the applicability of this technique were: (a) nonpreferential hydrolysis of triglyceride species; (b) absence of a substantial amount of complete hydrolysis; and (c) absence of a significant amount of acyl migration during the hydrolysis reaction. Although there was no evidence of preferential hydrolysis at the one-third stage, there was some complete hydrolysis, and acyl migration did not appear to be occurring at a significant rate. The validity of the procedures employed was demonstrated on a fat of known and unique structure, pig body fat. Therefore, the technique can give ~sults that may be used to establish general relationships. In cow milk fat the majority of the fatty acids were found to be uniformly distributed within the glyceride, except for C, and C~, which are predominantly in the external positions, and C~, which tends to concentrate in the two position.